This invention relates to a divisional operation system, and more particularly to a divisional operation system to obtain a quotient by repeating subtraction and shift operations.
In a divisional operation system, a register for storing dividends therein, a register for storing divisors therein, and a register for storing quotients therein are provided. Generally, a portion of the register for storing dividend therein is common to the register for storing quotients therein. Division is executed by repeatedly performing a first operation to subtract a divisor from higher order digits or figures of dividends and a second operation to shift the dividend to the left after the first operation is completed, to carry out the next subtraction. The quotient is obtained by representing signs or symbols of respective subtraction results with 1 and 0 to arrange them in succession.
When the dividend is considerably larger than the divisor, the quotient obtained as a result of division also becomes large, so the number of figures or digits of the register for storing the quotient becomes insufficient. Namely, the division will overflow, thus failing to obtain a correct operation result. For this reason, with the conventional divisional operation system, prior to the execution of an actual divisional operation, a comparative operation between the dividend and the divisor is performed to judge whether or not the division overflows.
As described above, since the comparative operation for examining whether or not the division overflows is carried out prior to all divisional operations in the conventional divisional operation system, there has occurred the problem that it takes an extra or excessive time, resulting in slow operation speed.